The present disclosure provides a dressing configured to cover a wound. The dressing includes a substrate layer, a contact layer and a readable pattern layer. The substrate layer is light-permeable. The contact layer is located at a side of the substrate layer, and the contact layer is configured to contact the wound or skin around the wound. The readable pattern layer is disposed on the contact layer. The readable pattern layer includes a plurality of positioning marks and a plurality of colored cells. The positioning marks are configured to define an information area. The colored cells are located in the information areas, wherein at least part of the colored cells includes a biological indicator, and the positioning marks and the colored cells are visible through the substrate layer.